Thread-starter for piping.



D. s. COGHRAN. THREAD STARTER FOR PIPING. IIIIIIIIIIIIIIIIII Y 7, 1910.

1,099,340, Patented June 9, 1914.

COLUMBIA PLANOGRAIH Cm. wAs lllllllllll c.

onrrnn srarrps PigTENT OFFICE.

DWIGHT S. COCHRAN,I OF DENVER, COLORADO, ASSIGNOB', BY MESNE ASSIGNMENTS,

TO THE 0CTAGON"IDIE AND TOOL COMPANY, OF DENVER, COLORADO,

TION OF COLORADO.

A CORPORA- THBEAD-STARTER FOR PIPING.

Patented June 5), 1914.

Application filed May 7, 1910. Serial No. 560,006.

To all whom it may concern Be it known that I,Dwionr S. Cool-IRAN, a citizen of the United States of America, residing in the city and county of Denver and State of Colorado, have invented a new and useful Thread-Starter for Piping, of which the following is a. specification.

My invention relates to improvements 1n thread starters for piping; and the objects of my invention are: First, to provide a thread starting die that can be applied to broken pipes or to pipes having battered or crushed threads, and require that a die be run over them in places where they cannot otherwise be repaired without being removed. And second, to provide a thread starting die that is especially adapted to repair broken air or steam pipes on locomotives and cars, and in steamsh1ps, automobiles, and around the radiators of and 1n other parts of buildings, without removing the pipes from their connected pos tions. attain these objects by the mechanism illustrated in the accompanying drawmgs, 111 which:

Figure 1,is a side elevation of a device embodying my invention. Fig. 2, is an end view of Fig. 1. Fig. 3, is a central longitudinal sectional view showing the device in position for cutting a thread on the end of a pipe. Fig. 4, is a transverse sectional view on the line 4cl of Fig. 3. Fig. 5, is a top view of one of the pipe-engaging dogs. And Fig. 6, is an end view thereof.

Similar letters of reference refer to similar parts throughout the several views.

Referring to the drawings, the numeral 1 designates apiece of metal pipe upon the end of which it is desired to cut a thread.

2 designatesa adapted to cut a pipe 1.

designates the body portion of my thread starting device. I term this body portion a plug, as it comprises a plugshaped portion, which is-of a diameter to fit easily within the pipe upon which the thread is to be cut, and of a length to extend far enough into the pipe to form a good support. This plug is adapted to extend partially into and partially out of the end of the pipe to be threaded, and its outer thread on the end of the end portion 1s provided with a slightly en 4, which is provided; extends into the pipe.

larged collar portion thread cutting die of a size with a thread of the same pitch as the thread that is to be cut on the pipe and that is made of a diameter that will enable a die to be screwed easily onto it and to be screwed from it onto the end of the pipe, as will be explained more fully hereinafter.

A reduced neck portion 5 is formed on the outer end of the plug, which extends outwardly from it to allow a wrench to be applied to the die between the end of the pipe 1 and a hand wheel 6, which is secured to the outer end of a stem 7 that extends rotativcly through the center of the plugto its opposite end, and which is arranged in the following manner: The plug is provided with an axial aperture 8, which extends through it from end to end. The entrance to this aperture at the neck portion of the plug is interiorly threaded for a short distance, and the stem 7 extends rotatively through the aperture in the plug, and its outer end is provided with a left-handed thread 9, that is adapted to screw easily into and out of the threaded end portionof.

the neck of. the plug a short distance, and the hand wheel 6 is secured to the extreme outer end of the stem in any suitable manner. The opposite end of the stem is provided with collars 10 and 11, which are formed on its inner end a short distance apart. These collars are positioned in a coimterbore 12, formed in the oppositccnd of the plug from its handle and concentric with its axial bore. The counterbore is made long enough to permit the collar portions to be moved to and fro in it as the clamping stem is screwed into and out of the plug. These collars are adapted to hold loosely between them the car portions .13 of a plurality of cam dogs 14, which consist of approximately triangular blocks of hardened steel which are pivotally mounted in slots 15, formed radially through the plug from its countorbore aperture 12 to its pcriphc al surface at cqui-distant points around its surface. The dogs are pivotally mounted on pins 16, which extend through lug portions 17 formed in the end portion of the plug by forming angled recesses in positions around the peripheral surface of the plug to leave the lugs on opposite sides of the cam lug recesses. The cam-dogs are each pivoted adjacent to the end of the plug that The cars 13 of the dogs extend radially into the axial aperture of the plug between the collar portions of the stem, while the pipeengaging portions of each cam-dog are pointed as shown at 18, and normally lie close to or below the pe ripheral surface of the plug, when the stem is screwed into the neck of the plug, until the hand wheel is against the neck portion of the plug. The angular point 18 of each of the cams is formed to extend slightly upward, and is adapted to embed itself into the inner surface of the pipes. These camdogs are positioned in their slots to stand with their pivotal ends adjacent to the inner end of the plug, and with their pointed ends extending toward the threaded band end of the plug and they are all arranged to be moved outwardly to engage the inner surface of a pipe or t release the plug from a pipe simultaneously,- depending on which way the hand wheel and the stem are rotated by the operator.

The operation of my improved die starter is as follows: The die 2 is placed over the inner end. of the plug and is screwed onto its threaded band portion beyond its shoulder 4. The plug is then inserted in the end of the pipe 1 against the shoulder 4 of the band, and is held there by one hand of the operator, while the other hand grasps the hand wheel and turns it to screw the stem 7 out from the neck portion of the plug, which outward movement of the stem draws the pointed ends 18 of all of the cams toward the front or neck portion of the plug simul taneously, and moves their pointed ends out- Ward beyond the peripheral surface of the plug until they all engage and are slightly buried in. the inner surface of the pipe, which firmly of the pipe, the operator being able by means of the hand wheel and threaded stem, to force the cam-dogs into the inner surface of the pipe to rigidly secure the plug to the pipe. A wrench is then applied to the die 2, and it is turned to screw upon the end. of the pipe and cut a thread on it as the threads on the threaded band of the plug are a perfect guide for it, as they are of the same size and pitch as the die and the threads that are to be cut on the pipe.

My invention is simple, strong, and is especially adapted for use in repairing broken pipes in places where it is inconvenient to take the broken pipe out of its position, such as around locomotives, steamships, steam and hot water radiator heating. ystems of buildings, automobiles, and for all places where it is impossible to apply the commonly used die stock and thread cutting machines.

Having described my vinvention, what I claim as new and desire to secure by Letters Patent, is:

1. In a thread starter for pipe, the combisecures the plug to the inside.

,bination of the pl nation of a plug adapted to extend into the ends of pipe and provided with slots in one end arranged at equi-distances apart around its peripheral surface, cam-d0gs pivoted .to the end of said plug in said slots and provided with edges adapted to extend into the inner surface of said pipe, a stem extending through said plug and threaded thereto, means for rotating said stem, and means connected with said stem for engaging and moving said cam-dogs to engage and grip, the inner surface of larged threaded collar portion on the opposite end of said plug from said cam-dogs, arranged to bear against the end of the pipe and arranged to fit the threads and to receive a thread cutting die adapted to cut a thread on said pipe.

2. In a thread starter for pipe, the combination with a plug adapted to extend into the ends of pipe, cam dogs on the inside end of said plug provided with a pipe gripping end, of the stem extending through said plug and rotatively threaded thereto and provided with collar portions arranged to engage and tomove said cam-dogs when said stem. is turned, the hand wheel for turning said stem, and the raised threaded collar portion on the outer end of said plug provided with a thread of the ameter as the thread to be cutvon said pipe and arranged to extendto the edge of the pipe and adapted to receive rotat-ively the die that is to cut the thread on said pipe in such a manner that said pipe, wit-h an 611-.

said die can be rosame pitch di- 9 tated by an operator and screwed from the thread of said plug onto said pipe in such a manner as to start said die to cutting a thread thereon.

3. A thread starter, comprising a. plug portion adapted to be inserted in a pipe, a threaded portion on the outer end of said plug arranged to bear against the end of the pipe, said threaded portion being provided with a thread of the same pitch as the thread to be cut on the pipe,rand of a diameter to enable a die screwed thereon to be screwed from the threaded portion ,of the plug onto the end of the pipe, a stem extending through said plug and threaded thereto, a plurality of cam-dogs pivoted to the inner end of said plug and arranged to be moved by said stem to move radially outward from said plug and engage the interior surface of said pipe, and means including a hand wheel secured to the outer end of said stem forcing said cam-dogs in and out of the inner end of said plug to cause said dogs to grip or to release the inner surface of said pipe.

4. In a thread starter for pipe, the comug provided with slots at one end, pins extending through said slots, an axial aperture extendingthrough said plug, a threaded portion on the opposite end of said plug from said slots and pins, said outside threaded portion being arranged against the end of said pipe and adapted to receive rotatably a die adapted to out a thread on said pipe, with cam-dogs pivotally mounted on said pins in said slots and having a chisel edge positioned to ex tend from its pivotal point at the inner end of said plug toward the die holding threaded portion of said plug, said cam-dogs being provided with a portion extending radially from their chisel point portion toward the axial aperture of said plug, the stem threaded to said plug, thehand wheel on the outer end of said stem, and the collar portions on the inner end of said stem arranged at a short distance apart and adapted to engage the inwardly radiating portion of said cam-dogs in such a manner as to move their chisel edges outwardly;

simultaneously together to engage and grip said plug to the inner surface of said pipe Copies of this patent may be obtained for five cents each, by addressing the or inwardly to release said cam-dogs and plug from said pipe as said stem is threaded into or out of said plug.

5. In a thread starter, a plug adapted to extend into a pipe, a stem extending through said plug and in screw-threaded engagement therewith, means for rotatin the stem, dogs 'pivotally mounted on Sill! plug having DWIGHT S. COCHRAN.

Witnesses Gr. SARGENT ELLIOTT, ADELLA M. FowLE.

Commissioner of Patents,

Washington, D. 0.

with or 

